Comparison of methods for the detection of gravitational waves from unknown neutron stars

Walsh, S. and Pitkin, M. and Oliver, M. and D'Antonio, S. and Dergachev, V. and Królak, A. and Astone, P. and Bejger, M. and Di Giovanni, M. and Dorosh, O. and Frasca, S. and Leaci, P. and Mastrogiovanni, S. and Miller, A. and Palomba, C. and Papa, M. A. and Piccinni, O. J. and Riles, K. and Sauter, O. and Sintes, A. M. (2016) Comparison of methods for the detection of gravitational waves from unknown neutron stars. Physical Review D, 94 (12): 124010. ISSN 1550-7998

Abstract

Rapidly rotating neutron stars are promising sources of continuous gravitational wave radiation for the LIGO and Virgo interferometers. The majority of neutron stars in our galaxy have not been identified with electromagnetic observations. All-sky searches for isolated neutron stars offer the potential to detect gravitational waves from these unidentified sources. The parameter space of these blind all-sky searches, which also cover a large range of frequencies and frequency derivatives, presents a significant computational challenge. Different methods have been designed to perform these searches within acceptable computational limits. Here we describe the first benchmark in a project to compare the search methods currently available for the detection of unknown isolated neutron stars. The five methods compared here are individually referred to as the PowerFlux, sky Hough, frequency Hough, Einstein@Home, and time domain F-statistic methods. We employ a mock data challenge to compare the ability of each search method to recover signals simulated assuming a standard signal model. We find similar performance among the four quick-look search methods, while the more computationally intensive search method, Einstein@Home, achieves up to a factor of two higher sensitivity. We find that the absence of a second derivative frequency in the search parameter space does not degrade search sensitivity for signals with physically plausible second derivative frequencies. We also report on the parameter estimation accuracy of each search method, and the stability of the sensitivity in frequency and frequency derivative and in the presence of detector noise.